This invention is directed to an all plastic dispensing closure for plastic containers and method of application.
In the field of plastic injection molded open head pails a transition is taking place toward all plastic closures. This movement is principally to accommodate environmental recycling concerns and, of course, also to effect attainable cost reductions. The market at this stage has determined that an all plastic dispensing closure can be snapped on to the upstanding opening neck of a pail lid and successfully meet the various performance criteria set by UN and DOT regulations. To date, however, those all plastic dispensing closures successfully commercialized still leave some gaps in the desirability agenda.
For example, U.S. Pat. No. 5,788,100 dated Aug. 4, 1998 discloses an all plastic snap-on closure made up of a flexible pouring spout surrounded by an annular sealing channel and fitted with an overlying screw cap. A locking ring is integrally connected about the periphery of the screw cap so as to extend radially outwardly of the spout sealing channel. In application the closure is pressed onto a circumferentially enlarged upstanding opening neck causing the sealing channel to snap thereover. During the closure application the locking ring is broken away from the cap periphery and axially pressed around the outer wall of the sealing channel so as to lock the same against the opening neck The result is a very strong closure container wall connection. The downside resides in the fact that the locking ring can be easily pried off without damage, leaving the closure exposed to undetected tampering and pilferage which negatively impacts universal acceptance.
Another example is U.S. Pat. Nos. 5,797,525 and 5,641,099 dated Aug. 25, 1998 and Jun. 24, 1997 respectively which also show an all plastic snap-on closure made up of a flexible pouring spout surrounded by an annular sealing channel and fitted with an overlying screw cap. These constructions also embody an outer locking ring integrally connected by frangible webs about the periphery of the screw cap. In application the closure is pressed onto a circumferentially enlarged upstanding opening neck causing both the sealing channel outer wall and the peripheral locking ring to snap thereover. This arrangement causes both the spout outer sealing channel and the peripheral locking ring to expand over the neck enlargement and then relies solely on the elastic memory of the plastic parts to radially contract below the neck enlargement and hold the parts tightly together. The principal problem with this construction is the inability under varied manufacturing conditions to consistently retain a tight seal due to elastic memory alone. In addition undetected tampering can also be readily accomplished by simply prying the fitting off of the opening neck
The invention closure and method overcomes these prior art deficiencies in a very simple and straight forward manner. As explained above, the current prior art practice is to one way or another, during application, surround the fully seated sealing channel outer wall with a locking ring introduced as an integral part of the closure. In accordance with the invention the locking ring is instead integrally molded in the pail lid as a raised annular collar spaced from and surrounding the upstanding opening neck The outer wall of the spout sealing channel is, during application, then squeezed into the annular gap formed between the neck and the collar creating a very strong, liquid tight engagement between the closure and the pail lid. The advantages of the invention closure and method are immediately apparent There is no breaking away of relatively fragile parts which are then stretched around other parts. There is no reliance on elastic memory for holding parts together. Most importantly, the tamper resistance of the invention closure is substantially increased, as there is no readily undetectable way the fitting or any part thereof can be pried off the pail lid. This characteristic in itself clearly distinguishes the invention closure over other snap-on all plastic closures currently in use. Moreover the ultimate simplicity of application to the pail lid easily constitutes a further advance in the art.
It is accordingly a principal object of the invention to provide a new and improved all plastic closure for containers and method of application.
Another object is to provide an all plastic dispensing closure, which is interlocked with a unique lid opening configuration.
A further object is to provide a new pouring spout closure that permanently engages the pail lid opening with superior tamper resistance.
Other and more detailed objects of the invention will in part be obvious and a part pointed out as the description taken in conjunction with the accompanying drawing proceeds.